NASCAR legend Kyle Busch died from severe pneumonia, which progressed into sepsis … according to a statement from his family.

The AP reports, according to a family statement, Busch passed away “after severe pneumonia progressed into sepsis, resulting in rapid and overwhelming associated complications.”

The outlet reports the family received the medical evaluation on Saturday, citing a news release from Dakota Hunter, VP of Kyle Busch Companies.

As we reported … Kyle died Thursday after being hospitalized with a severe illness.

Kyle’s death came 11 days after a NASCAR Cup Series race in which he radioed to his crew and asked for a doctor to give him a “shot” after he finished the race.

On TV, they noted Kyle had been battling some sort of sinus cold that was made worse by the intense G-forces and elevation changes at New York’s Watkins Glen course. That race was on May 10.

Despite the health issue, Kyle kept competing … winning a Truck Series race on May 15 and then competing in the NASCAR All-Star Race on May 17, just four days before his death.

Kyle was 41.